Timing a 4020 injector pump

[gwillhoite]

1970 JD 4020, following the service manual with clocking the oil pump and how the oil pump should be positioned after installed, I am still not sure if I am right. The manual states that the slot in the oil pump gear should be at a 15 degrees from being parallel to the cam and the notch in the gear should be facing the cam. Sorry for the long post, just asking for verification that I have this thing right. Too much money in this engine to screw up.
Thank you all for the help.
Gary

 

[Dieseltech]

That's correct, BUT you MUST have the CAMSHAFT in the correct spot FIRST. The front number one piston at TDC and the rocker arms loose on the COMPRESSION stroke, the
number six rockers will be on the exhaust closing/intake opening overlap. The CAMSHAFT determines which piston is ready to fire, since BOTH one and six pistons are at TDC
together.
I've repaired 3010/3020/4010/4020 pumps with the drive shaft in 1/2 turn off BECAUSE the oil pump was installed 1/2 turn off, and mechanic didn't want to drop the pan to correct the oil pump being installed wrong, so they just turned the injection pump 1/2 turn to make it work as is.

 

[gwillhoite]

Thanks Dieseltech. Yes, I still have the front timing cover off and I verified timing marks are correct and TDC on the flywheel is also correct.
Thanks again. I am going to try and finish this rebuild.
Gary

 

[JD Dave]

Thanks, Diesel Tech. You give us all some mechanical details and tidbits that we missed in the tech manuals.

 

[Dieseltech]

What I would have done on the 3010/3020/4010/4020 injection pump drive is made the tang CENTERED like the 1010 drive is, that way if the pump is installed wrong at least the injection pump is not wrecked, engine just won't run. Too many times the offset drive is STILL installed wrong, and pump lacks about 1/8 inch from setting down on the block. The installer will then try to pull it down in place with the stud nuts, then first time engine is turned the hydraulic head is seized and the drive shaft broken. I've seen that happen several times in my forty-five years and counting of fuel system repair.

 

[grwrench]

hello;; the oil pump slot has to be 15* the other way for the inj. pump to time up.. the arrow has to be toward the block as you have,,, BUT the slot has to be slanted toward #1
cylinder,,so the arrow sorta points to #6 cylinder..

 

[gwillhoite]

I believe that you are right grwrench. I started to place the inj. pump in last night and the way you described how the slot needs to be will allow for the inj. pump to be in time.
I have a couple of service manuals and found this picture.
Thanks everyone.

 

[JIM MN]

Yes; grwrench is is correct, 15 degrees the other way !!